There is a fine line between exercises that strengthen the joints of the body and increases flexibility and those that could make the symptoms of osteoarthritis (OA) worse. Even the results of research can send conflicting messages. Some studies show an association between mechanical strain and knee arthritis, while others have proven that strengthening joint-supporting muscles can reduce pain and enhance both flexibility and mobility. A.J. Cianflocco, MD, Program Director for Cleveland Clinics Primary Sports Medicine Fellowship, and physical therapist George Sibel, DPT, provide some direction on which exercises to avoid and suggest the types of activities that can help you diminish or prevent some of the symptoms that accompany OA. "Activities to avoid are the ones that hurt, particularly while youre engaged in the activity," says Dr. Cianflocco. "Pain is a red flag that tells you to stop what youre doing and perhaps eliminate it from your exercise routine altogether. If the discomfort develops only after an activity, you may be able to get back to doing it with either less intensity, fewer repetitions, or for a shorter period of time."